The inner layer is comprised of glucan polymers and chitin (N-acetylglucosamine polymers). This layer is constructed mainly (80 to 90%) of β1,3-glucan chains with some β1,6-linked glucan branches. Polymers of β1,6-glucan chains make up most of the remainder of the inner layer (8 to 18%), with chitin chains representing the smallest fraction (1 to 2%). This layer is largely responsible for the mechanical strength and elasticity of the cell wall owing primarily to the helical nature of β1,3-glucan chains